Food treatment process



FOOD TREATMENT ROCESS Filed April 4, 1942 13 Sheets-Sheet 1 C//ru5 fru/e Oranges Ue/ .scrubbing f4 .ur/ce dry ing Free 5m? eaeralf/'an/WeaSUr/ng Kan cen /fa/e ATTOBNE Y May 4, 1948. M. E. DUNKLEY FOODTREATMENT PROCESS Filed April 4, 1942 13 Sheets-Sheet 2 May 4, 1,948.V ME, BUNKLEY 2,440,676 l y. FOOD TREATMENT PROCESS Filed'April 4, 1942 1ssheets-sheet s 'm J m mx: NV Q' WIE-:EA-

IVENTOR Me/vj//e f Dunk/ey ATTORNEY avm May 4, 1948.

M. E. DUNKLEY FOOD TREATMENT PROCESS 13 Sheets-Sheet 4 Filed April 4,1942 INVENToR Me/v//e f. Hunk/ey ATTORNEY May 4, 1948. M. DUNKLEY2,440,676

I FOOD TREATMENT PROCESS Filed April 4, 1942 13 Sheets-Sheet 5 ArToRNEYM. E. DUNKLEY l FOOD TREATMENT PROCESS Filed April 4, 1942 15Sheets-Sheet 6 lll l! E t E E E Cf.

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C E E C C Il VENTOR.

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FOOD TREATMENT PROCESS Filed April 4, 1942 13 Sheets-.Sheef 9 IN VENTOR. /We/w//e Dunk/ey BY May 4, 1948.

M. E. DUNKLEY FOOD TREATMENT rRocEsS Filedprn 4, 1942 13 Sheets-Sheet10l INVEN TOR.

. /f/e/v/Y/e f. UnL//eg @Aem TTOEA/EY nimm .ImHlrbuHl M. E. DUNKLEY FOODTREATMENT PROCESS May 4, 194s.

Filed April 4, 1942 13 Sheets-Sheet l1 SZ/S um ...www i sa n N m s m\\\\m\ n -------I-I IIQVL MS.

May 4 1948- f M. E. DUNKLEY l 2,440,676

FOOD TREATMENT PROCESS` Filed April 4. 1942 13 Sheets-Sheet 112 lax/@M2MMay 4, 1948. M. E. DUNKLEY Foon TREATMENT PROCESS 'Filed April 4. 1942I125 Sheets-Sheet 13,

...rb ...l mHrnH ATTOENE'Y reame May 4, 1948 UNITED STATES PATIENTOFFICE Application April 4, 1942, Serial No. 437.661

(ci. sei- 155) s claims. l

This invention relates generally to processes and apparatus for thetreatment and handling of various food lproducts, for the purpose offorming marketable food products in dehydrated or concentratedcondition.

It is an object of thel invention to provide a process and apparatus ofthe above character having improved features with respect to theprocedure and apparatus employed for dehydrating or concentrating thefood material. In this connection the invention is characterized by useof relatively low temperatures for dehydration or concentration,together with the fact that during both preliminary preparation andsubsequent evaporation of moisturerom the material,

it is in contact with a sterile and oxygen-free atmosphere.

A further object of the. invent-ion is to provide a process andapparatus of the above character characterized by the fact that thetemperatures employed during dehydration are regulated by thetemperature of the material being treated. The material itself is thussubjected to evaporation without danger of impairment of its desirableproperties by heat.

A further object of the invention is to provide a novel apparatus forcarrying out drying or concentrating operations according to the presentprocess, and which is characterized by features including the following:a relatively high commercial capacity; the handling of material in trayswhich are arranged to be emptied without contact with the air; and ameans to facilitate quick loading of material into the drying trays; andprovision for unloading the separate trays before they are removed fromthe dehydrating unit.

Another object of the invention is to provide a novel method forremoving the lpeel or skin of fruit, the method being characterized bythe freezing operation followed by removal of the skin by attrition.

' .Another object `of the invention is to provideV an improved methodand apparatus for removing dissolved oxygen from fruit juices.

Another object of the invention is to provide a process and apparatusparticularly adapted for the purpose of producing preserved concentratesfrom citrus fruit. In this connection the invention is characterized bythe preferred Vuse of a number of novel operations and equipment for thesame, including preliminary cleansing of the fruit. sterilizing of thefruit, drying of the surfaces of the fruit after such sterilizingfreezattrition, removal of juice from the flesh of the fruit. removal ofdissolved oxygen, concentration by evaporation in such a fashion as toleave the avor and food value of the juice substantially unimpaired, andthen packaging of the concentrate in sterile containers.

Another object of the invention is to provide improved method andapparatus for the packaging and sealing of the finished product,.characterized particularly by the -fact that the material remains at alltimes in a sterile and oxygen-free atmosphere, thus insuring permanentsterile and oxygen-free conditions inside the final packages. Y

Additional objects of the invention will appear from the followingdescription in which the preferred embodiment has been set forth indetail in conjunction with the accompanying drawings.

Referring to the drawings:

Figure 1 is a flow sheet Iillustrating a complete process for themanufacture of citrus juice concentrate;

Figure 2 is a diagrammatic layout showing the various pieces ofequipment for carrying out the flow sheet of Figure 1;

Figures 3A to 3K inclusive are side elevational views intended to beplaced end to end, and showing equipment as follows:

Figure BA-Conveying equipment for manual inspection and sorting ofcitrus fruits;

Figure 3B--Equipment for the wet scrubbing of the citrus fruit, togetherwith one end portion of i equipment for immersing the fruit in asterilizing solution;

Figure 3C-The remainder of the apparatus for irnmersing the fruit in asterilizing solution, md a portion of the equipment for drying the ruit;

Figure 3DA portion of the equipment for drying the fruit, and the inletportion of the apparatus for freezing the fruit;

Figure 3E-The remaining portion of the apparatus for freezing the fruit,and the attrition mill for removing the peel;

Figure :iF-The disintegrating mili for pulping I the fruit flesh, thecentrifugal filter for filtering out the coarser pulp, and the apparatusfor deaerating the juice;

Figure 3G-The storage and measuring tanks for the deaerated juice, andportion of the concentrating or drying unit, particularly the loadingend of the same;

FigureBAH--The loading chamber of the drying unit, partly in crosssection, and a portion of the` ing of the fruit, removal or the frozenpeel by 56 main drying chamber of this unit;

Figure 3J-'I'he discharge end of the drying unit and the unloadingchamber from which the cars are removed:

Figure 3K-The storage tank for receiving the nished concentrate and theapparatus for placing the concentrate into sterile containers.

Fig. 4 is a plan view of a portion of the sorting conveyor shown inFigure 3A;

Fig. 5 is an enlarged cross sectional detail taken along the line 5--5of Figure 3B;

Figure 6'is a cross sectional view taken along the line 6-6 of Figure3C;

Figure 7 isl an enlarged cross sectional detail showing details of thecentrifugal lter for removing the coarser pulp from the juice;

Figure 8 is an enlarged cross sectional detail showing the constructionof the deaerating equipment;

Figure 9 is a cross sectional detail taken along the line 9-9 of Figure3F;

Figure 10 is a cross sectional detail taken along the line III- I0 ofFigure 3H;

Figure l1 is an enlarged cross sectional detail showing the manner inwhich the filling nozzles are disposed to deliver material into thetrays;

Figure 12 is an enlarged detail showing a plan view of one of thecharging nozzles, as it delivers material into a tray;

Figure 13 is a side elevational view in cross section of Figure 3Jshowing a portion of the unloading chamber, and the means utilized fordischarging the trays; and

Figure 14 is an enlarged detail in plan showing one of the rotary valvesfor transferring containers into and from the filling equipment ofFigure 3J While the present invention is applicable to treatment of aWide variety of materials, including materials in both liquid and solidform, it will be described particularly in connection with themanufacture of a preserved concentrate from citrus fruit such asoranges, lemons or grapefruit. Because of certain features of my processwhich will be presently described, it is capable of producing apreserved citrus fruit concentrate having all of the natural avor andnutritive properties of the original juice, and which can be re-mixedwith water to produce a reconstituted juice for use in place of freshjuice.

Before considering the various features of equipment illustrated in thedrawings, a brief explanation will be made of Figure 1 which shows thesequence of operations which I prefer to employ with citrus juice. Thus,the fresh fruit is rst subjected to inspection III, where defective orspoiled fruit is removed. It is then subjected to wet scrubbing II, forthe purpose of removing all foreign matter from the other surface. Thescrubbed or cleaned fruit is then subjected to sterilizing I2, byimmersion in a sterilizing solution.

Following sterilization, the fruit is passed to the cold dip I3, whereit isirnmersed in relatively cool sterile water. 1 The fruit then passesto the drying operation I4 to remove surface moisture, after which itpasses to the freezing operation I5. Freezing is carried out so that atleast the peel is frozen, together with a part of the fruit flesh nearthe peel. Y

Following freezing the fruit is passed to the peeling operation IB wherethe frozen peel is removedv by attrition. This operation results information of a peel slurry which can be used to make various products,as for example vitamin food materials and vitamin concentrates. 'I'hefruit flesh passes to the disintegrating operation I1, where it isreduced to a divided mass. This is then subjected to a screeningoperation I8 for removing the coarser pulp from the juice. The juice isnow in condition for further treatment to form a preserved concentrate.

Immediately after being freed from the coarser pulp, the juice issubjected to treatment for removing absorbed oxygen. I prefer that thisbe lin contact with a sterilizing drying gas devoid of oxygen.

The concentrate resulting from operation 22 is then packed into suitablesterile containers as indicated at 23 to produce a nal packaged andpreserved product.

A general diagrammatic layout of apparatus for carrying out the variousoperations is shown in Figure 2. In this case the citrus fruit is firsthandled by the sizers 26 which deliver the fruit to the storage bins 21.From these bins the fruit is passed to the inspection unit 3l where thefruit is inspected manually and defective fruit discarded. From theinspection unit the fruit passes to the wet scrubber 32, and thensuccessively to the hot dipping unit 33 and the cold dipping unit 34,and the surface drier 35. From the drier the fruit passes to the freezer36, and the frozen fruit then passes to the abrasion peeler 31, wherethe peel is removed. The body or flesh of the fruit passes to thedisintegrator 38 and the resulting macerated mass thenpasses to thecentrifugal separator 39. The juice from the separator passes throughthe deaerating equipment 40, in which absorbed oxygen is dispersed witha sterile inert gas, and the de-oxidized juice then passes to thestorage tanks 4|. From these tanks the juice can pass to the measuringtanks 42, and from thence to the loading chamber of the dehydrator orconcentrator unit 43. The concentrate from the outlet end of thedehydrating unit is delivered to the storage tank 44, where it is keptat a relatively low temperature, and from these tanks the juice passesto the filling and packaging machinery 46. During its treatment in thesuccessive units, the juice at no time is subject to eithercontamination or oxydation,

Referring now the various features of appara- I tus showndiagrammatically in Fig. 2, the sizer 26 and storage bins 21 require noparticular description, as these may be conventional or may vary indifferent instances. The inspection and sorting equipment 3| may beformed generally as shown in Figures 3A and 4. In this instance itconsists of a conveyor belt 5I divided by guide rails into a mainportion 52 and side portions 53. A chute 54 from the storage bins 21delivers fruit to the belt portion 52, and while the fruit is carriedalong it is inspected, and defective fruit shifted to the side beltportions 53. The discharge the surface of the fruit is vigorous scrubbedwith bristles while'the fruit is kept wet with water. The machineillustrated is formed with a auaovo closed housing s1. within whichthere man ena,..-

less belt 56 in conjunction with the rotary scrubbing rolls 59 and 6|.The endless belt 58 is carried by sheaves or pulley wheels 62 and 63,one of which is driven at a suitable rateas indicated. Suitable bristles64 of relatively stiif fiber are mounted upon the exterior of this belt56, and the rolls 59 and 6| are provided with similar bristles 59 and 6|are likewise driven at a. suitable speed,

such as 450 R. P. M., and in opposite directions as indicated.

. The scrubbing apparatus operates as follows: As the fruit is deliveredfrom the chute 55 into the receiving end of the housing 51, it isdelivered uponthe upper run of the belt 56 and commences its advancethrough the machine in the region between the rolls 59 and 6|.V Whileadvancing, it is ricocheted vigorously back and forth into contact withthe rolls and the bristles on the upper run of the belt 58, while at thesame time it is subjected to a spray of water. This serves to remove allforeign material from the skin of the fruit. Finally the fruit isdelivered from the upper right hand end of the machine as shown inFigure 3B, into the discharge chute 69.

' The hot and cold dipping units 33 and 34 are shown in Figures 3B and3C. together with Figyure 6. Discharge chute 69 from the scrubbing unit32 delivers the fruit to a shaker conveyor 1|, which in turn deliversthe fruit to the inlet 12 of the hot dipping units 33. These units makeuse of closed tanks 13 and 14, together with sultable conveying meanswhereby the fruit is conveyed through these tanks successively. Theconveying means includes lthe endless conveyor chain 16 which engagesover a series of sprockets, including the end sprockets 11 and 18,sprockets 19 and 8| in tank 13, sprocket 92 between the tanks 13 and 14,sprockets 63 and 84 in tank 14, and sprockets 86 and 81 at the deliveryend of The liquid in tank 14 is cool sterile water, and the immersion ofthe fruit in this water servos to prevent undesirable penetration ofheat into the flesh of the fruit. 'Ihe temperature of the water in thistank may be of the order yof from 50 to 76 F. It water of thistemperature is not available, the tank can be equipped with coolingpipes or coils |62. The water can be maintained sterile by means of asterilizing agent like chlor ne.

The drying unit 35 is constructed similarly to the scrubber 32, exceptthat no water spray is provided. It consists of anyupwardly inclined theapparatus 34. Sprocket 86 is driven by motor 88 through the belt 69 andgears 9| and 92. Spaced plates 93 are mounted upon the chain or belt 16so that rows of fruit can be retained between successive plates. Ahousing or shroud 94 houses the moving parts of the conveyor from thetime the fruit is received through the inlet 12 until it is deliveredinto the tank 13. Similarly the moving parts `of the conveyor passthrough housing 96, which connects the tanks 13 and 14. A similarhousing 91 encloses the moving parts of the conveyor as they leave thetank 14, and this housing connects with the inlet chute 98 of the dryingmachine 35. In passing through the tanks 13 and V14, the plate 93 passesbeneath the horizontalbaille walls 99 which serve to retain the fruit inplace between the plates.

The liquid medium in tank 13 is water, together with a sterilizing agentsuch as chlorine. The temperature of the water is maintained at anelevated value, such as of the order of 210 F. as by means of burners orelectrical heaters 16|. The unit can be made to retain the fruit in thehot dip for a period such as from 5 to 6 seconds.

housing |63, which has spaced brushing rolls |64, and the brush equippedbelt |66. The rolls |64 are driven together with the brush equippedconveyor |66 in the same fashion as the scrubbing unit, with the resultthat the fruit passes through the space between the brushing rolls 164with a spinning and ricocheting action, until being finally delivered tothe discharge chute |66 (Figure 3D). The fruit is generally confined tothe space between the rotary brushes |64 by pipes or rods correspondingto the spray pipes 61 and 66 (Figure 5).

The freezing unit 36 shown in detail in Figures 3D and 3E receives thefruit from the drier 35. As the fruit is delivered through the spout|68, it is carried vupwardly by the bucket conveyor |69, which in turnis enclosed within the housing Il l. As the fruit is dropped from theupper end of the conveyor |69, it is delivered to the inlet chute ||2 ofthe freezing unit 3B.

The freezing unit 36 preferably consists of an insulated housing ||3,within which is a ser-ies of slow moving endless belt conveyors II4, ||5and IIB. Freezing coils ||1, which connect with suitable refrigeratingequipment, are disposed above the upper runs of the conveyors. 'I'.hefruit is carried to the right by the conveyor I|4 and then drops fromthe right hand end of this conveyor upon the receiving end of theconveyor ||5. The conveyor ||5 carries the fruit to the vleit hand endwhere it is again dropped upon the receiving end of conveyor ll6. Theright hand end of conveyor ||6 finally delivers the frozen fruit to thedischarge spout ||9.

`The time period of retention of the fruit in freezing unit 36 is suchthat all of the peel and at least the. outer portionof the esh isfrozen. The penetration of the freeze may be deeper than necessarywithout detrimental results. The time period of retention will dependupon the kheat absorbing capacity of the coils ||1 and the character ofthe fruit being frozen.

After being delivered from the freezing unit, through chute ||9, thefrozen fruit is lifted by the enclosed elevating conveyor |2| anddelivered through the inlet |22 of the peeling or abrasion machine 31.This machine can be constructed like the Urschel ycontinuous vegetablepeeler. From the feed hopper |22, the fruit passes back and forth over aseries of rotating attrition rolls |23, |24, |25 and |26. Instead ofhaving these rolls coated with Carborundum, as is the case with Urschelsvegetable peeler, I use metal spines, as for example spines closely setupon the peripheries of the rolls and 1A; inch in length. The variouscompartments of this unit are also provided with spray pipes |21 andduring operation of the machine, a small amount of sterile water issprayed upon the fruit. 1

The peel removed from the fruit in unit 31 is in the form of a slurryand can be withdrawn through pipe |28. The meat of the fruit isdisandere charged through chute |29. During attrition of the peel, thepeel d-lssolves so that the peel slurry is relatively fluid, although acertain amount of the flesh remains frozen, particularly that partadjacent the peel. Therefore, even though the flesh is penetrated to aminor degree by the abrasive action of the rolls. no substantial amountof juice'is lost, and the body of the fruit remains firm. -Peel oil isremoved together with the slurry through pipe |28, so that substantiallyno peel oil finds its way into the juice subsequently extracted from themeat.

I'he freezing procedure for removing the pe can be applied to productsother than citrus fruit. For example, it can be applied to thin skinnedfruit like plums, or products like tomatoes.

Prior to peeling, the juice is protected by the peel. However, inpeeling if the peel itself contains contaminants such as micro organismswhich promote Aspoiiage, the juice will be contaminated. Therefore,following the hot dipping unit the fruit is kept out of contact with theatmosphere. 'I'his is accomplished by enclosing the various units andthe transfer means between the same and by maintenance of a sterilenon-oxidizing gas in the enclosures. Thus at various points, pipes |30are provided for bleeding in a sterile inert gas devoid of oxygen, andthis gas may gradually escape from different points of the equipment ormay pass out through special vent pipes.

From the peeler 31 the fruit is delivered through chutes |29 to thedisintegrating unit 38 (Figure 3F). 'I'his disintegrator is preferablyof the vertical hammer mill type, in which a vertical rotor operateswithin a cylindrical screen. Various types of disintegrators can beused, but the one shown in the Rietz Patent No. 2,153,590 will give goodresults. Briey, this disintegrator consists of'a rotor |3| provided withblades or hammers and driven by lthe electric motor |32. 'Ihe fruit isdropped into the zone of operation of the rotor and disintegrated byaction ofthe hammers. The disintegrated material passes through thecylindrical screen |33 and downwardly through the discharge conduit |34to the centrifugal lter 39.

The type of centrifugal filter illustrated (Figures 3F and 7) consistsof a housing |36, within which there is a horizontally disposedcylindrical screen |31. Fitted within the screen |31 there is a feedscrew |38. the thread or flight of which is formed of resilient rubber.Screen |31 is rotatably carried by the end shafts |39 and |41, which aresuitably journaled to the end walls of the housing |36. The shaft |42 offeed screw |38 is journaled concentrically with the screen shafts |39and |4|, and the outer ends of shafts |4| and |42 are provided with thedriving gears |43, |44. A motor |46, together with driving chains |41and |48, is shown for driving the sprockets |43 and |44. Both the screenand the inner feed screw are driven in the same direction, but the feedscrew is driven slightly faster than the screen, so that such relativemovement causes a progression of pulp from the inlet end to the righthand ceived within this screen |31, and centrifugal force causes juiceto pass through the screen to the drain pipe |49. The coarser pulpgradually progresses under the urge of the feed screw |38, until itreaches the right hand discharge end of the screen, where it isdelivered to pass out of the housing through pipe I5 vAn inertnon-oxidizing atmosphere is also low the freezing unit. For this purposeI have shown the gas inlet pipes |50.

The deaerating equipment 40 which follows the centrifugal illter 30consists of an extended cylin drical shaped housing |53, which has itsleft hand inlet end connected to the juice pipe |49. Extending throughthe lower part of the chamber |53, there is a rotating shaft |54 whichcarries the beaters |56. The ends of shafts |54 have journals |51 and|58 in the end walls of the chamber |53, and an extension of this shaftis shown directly coupled to the motor |46. A relatively high rate ofdriving speed can be used, as for example of the order of 1,500 R. P. M.A pipe |6| connecting with the right hand end of chamber |53 serves toremove the deaerated juice. This pipe can be connected to a gas trap |62to remove any entrained gas. Pipe |63 is shown connecting near the inletYend of chamber |53 for introducing an inert dispersing gas, as forexample a nonoxygen containing gas such as will be presently described.Pipe |64 serves to continuously vent gas from the chamber, and this pipeis shown connecting to the trap |65 whereby entrained juice can bereturned to the chamber through pipe |66.

Within the chamber |53 the juice is violently agitated to' formvirtuallya homogeneous mass comprising a mixture of liquid and gaseous phases,thereby insuring intimate contact between the juice and the dispersinggas.

From the trap |62 the deaerated juice is deliv'- ered by pipe |61 andpump |63 to the elevated storage tanks 4|. Distributing valves |69 makeit possible to distribute the juice to any one of these tanks asdesired. Each tank is shown provided with a vent valve |1|, to vent offgas from above the liquid, as the tank is being filled. Also valves |12control communication with a gas pipe |13 whereby an inert sterile gascan be introduced into any one of the tanks. Agitators |14 in each tankprevent undesirable settling vat this point. Valves |16 controlcommunication between the lower ends of the tank and the common outletpipe |11. This pipe in turn connects through valves |18 to themeasuringtanks 42. The measuring tanks may be made of glass or like transparentmaterial, or in any event they should be provided with level indicatingmeans to enable handling of predetermined amounts 0f juice. Manualvalves |8| and |82 control communication between these tanks and the gaspipe |13, whereby gas under pressure can be introduced into eithermeasuring tank to expel the juice. Valves |83 control communicationbetween the lower ends of the measuring tank, and the delivery juicepipe lines |84. Both measuring tanks are also provided with ventingvalves |85, so that gas can be vented of from the space above theliquid, as the tank is being filled.

It will be evident that with the arrangement of storage and measuringtanks described above, it is possible to maintain the juice at all timesout of contact with the air, and only in contact with an inert gasdevoid of oxygen. Also the juice can be delivered as desired to themeasuring tanks, and from thence the juice can be expelled by gas underpressure through the discharge pipe |84.

The drying unit 43 is of special construction adapted to handle thematerial in trays. In general, this unit includes the main dryingchamber or tunnel |86, the loading chamber |81 (Figures 3G am 3H) andthe unloading chamber |88 (Figures 3J and 13). 'I'he main drying chambermaintained in the units just described which folis in the form of a longtunnel as indicated diagrammatically in Figure `2. A trackway |88extends the entire length of this unit. and the 'cars |8| which operateon this trackway have racks t |82 for carrying the spaced trays |88.Referring particularly to the loading chamber |81 shown in Figure 3H,the chamber has a hinged door |84 which when opened permits a car loadedwith trays to be introduced into the unit. From this 4loading positionthe car can be transposed into and this pipe is connected by hose 28| tothe juice pipe |84. A series of individual nozzle pipes 282 extend frompipe |88, through the door |84, and

have their inner ends arranged to be disposed between adjacent trays inthe manner shown in Figure 11. Valves 288 control the flow of juicethrough each individual pipe. A valve controlled pipe 284 is showncommunicating with the load- .lng chamber |81 in order to introduce aninert gas devoid of oxygen. The upper part Y of this chamber is alsoshown provided with a valve controlled vent pipe 288. It will be evidentfrom the foregoing that when a car containing empty trays is placedwithin the loading compartment |81, and the door |84 closed, pipes 282are automatically disposed in position to discharge juice into theseveral trays. Now by successively opening the valves 288 an operatorcan discharge measured quantities of juice into the trays. After all ofthe trays have been lled, the sliding door or l v gate |88 is lifted.and then the hydraulic ram |81 is operated to smoothly advance the carinto the main drying compartmenty |88. To insure oxygen-free atmospherein chamber |81, before the trays are filled and immediately afterclosing the door |84, an oxygen-free gas is introduced into thecompartment through pipe 284 while pipe 288 is open to permit thedisplaced air to escape.

platform can observe the trays through lthe window 2|8. A pair ofresilient rubber sleeves |21 are also mounted within the same sidewalls, below the window 2|8, and these sleeves are arranged so that thetwo arms of the operator may be positioned withinthe same for graspingand moving the trays, while at the same time preventing the entrance ofexterior air. t Below the region of the sleeves 2|1, there is a hopper|28 which in turnconnects with the tank 2|8. Pipe 22| connects this tankto the'storage tanks 4I. The upper part of tank 2|8 is connected tovalve controlled gas and vent pipes 222 and 228. Also a valve 224 isinterposedbetween the hopper 2|8 and the tank 2|8, andv is shown beingoperated by the exterior handle 228. Directly below the region occupiedby a car inthe unloading chamber., there is a hydraulic Ilift orelevator 221 which 'is arranged to be stopped and started by theoperator. By means of this elevator the operator may lift the completecar and trays by successive steps, to facilitate the grasping of traysas the -of oxygen by permitting now of an inert gas through pipe 228.with venting of gasthrough. pipe 28|. After thoroughly flushing out theoxygen.'pipes 228 and 28| are closed, and the sliding In order toprovide a gate |88 which will move t freely and at the same time willprevent excessive leakage to the atmosphere,l I have shown anarrangement in which the gate operates within a 'vertical guideway 288with the upper edge of the gate attached to the operating andcounterbalancing chain 288. Extending entirely aboutv the peripheraledge lportion of the gate and mounted within the adjacent structure ofthe drying chamber |88, there is an inflatable tube 2| of suitableresilient material such as soft vulcanized rubber. This tube isconnected to a valve controlled hose or pipe 2|8 whereby it can beinfiatedlby air under pressure, or deflated by venting the air to theatmosphere. one side wall of this tube presses against the adjacentsurface of the gate |88, as shown in Figure 10. to provide a relativelygood gas-tight seal. When deflated, the gate has ample clearance forfree movement.

A novel construction for the unloading chamber is shown in Figures 3Jand 13. Thevdoorway 2 2 communicating between this chamber and the maindrying tunnel is normally closed by a sliding gate 2| 8, `like the gate|88 at the inlet end of the drying tunnel. Alongside one wall of theunloading chamber, there is an operators platform 214 and an operatorstanding upon this When inflatedv gate 2| 8 is raised. Assuming thatthis is being done inconjunction with the introduction of a freshlyloaded car into the receiving end of the drying chamber, the series ofthe cars in the drying chamber advance toward the outlet end, thusforcing the one car into the unloading chamber |88. A hydraulic ram 282'can be `used to engage the car for the purpose of forcing it into aposition free of the outlet doorway 2|2. Now the sliding gate 2 I8 isclosed and anoperator with his hands in the sleeves 2I1, and standingupon platform 2|4, grasps the top tray on the car, and pulls itvforwardly to a tilted position substantially as shown in dotted linesin Figure 13.

With concentrations which are ordinarily obtainable. as will bepresentlydescribed, the material in the trays will be too thick `te flow freely.Therefore, it will be necessary for the. operator to scrape theconcentrate from the trays by means of a suitable tool. When thematerial in one tray has been discharged, it is placed back upon thecar, and then the next tray withdrawn. As successive trays are unloaded,the operator causes the lift 221 to raise the car and trays bysuccessive steps, thus making all of the trays readily accessible. Theconcentrate delivered into the hopper 2|8 is permitted to ilow down tothe tank 2|8. When this tank has been illled, pipe 22| is opened, valve224 is closed, vent pipe 228 is closed, and pipe 222 is opened to permitgas under pressure to flow into the upper part of tank 2|8. thusexpelling the concentrate into the storage tank 44.

Referring to Figure 2, a gas circulating system through this conduit'ispassed through the cooler 2.84, heater 288, blower 288, and fromV thenceback into the drying, tunnel near the loading chamber. The cooler 234contains suitable refrigerated heat absorption units and serves to chillthe gas to a temperature depending upon the conditions of operation, butwhich in the case of citrus juice may be of the order of from 40 to 50F. In conjunction with this cooling, considerable moisture is condensedfrom the gas. The heater 235 circulates the gas over steam heated units,whereby the temperature of the gas is elevated to a value such as of theorder of from 70 tov 100 F. One or more thermostats can be provided tosecure automatic temperature control.

As shown in Figure 18, the controlling thermostat 231 is mounted on thetop of the drying tunnel and near the unloading chamber. It is mountedfor vertical adjustment so that it can be directly inserted into theliquid carried in the top tray of the last car in the tunnel (nearestthe unloading chamber). This thermostat is connected by known methods tocontro1 the heater 235, so that when the temperature of the concentratecarried by the last car reaches a predetermined maximum value (such as78 F.) further heating of the gas is interrupted. Thus the temperatureof thegas is regulated and kept within safe limits -by the temperatureof the material.

Figure 3K shows a suitable filling unit which will enable introductionof the concentrate into sterile containers without permitting contactwith the atmosphere. Thus in this instance a belt conveyor 238 isprovided to vcarry the ,lars 239 or like containers to lling positions.The upper run of this conveyor is enclosed by the housing 240, the endsof which are equipped with conventional rotary valves 24 I.

An intermediate `part of the housing 240 is formed to provide anupwardly extending filling chamber 242, one side of which is providedwith rubber sleeves 243, like the rubber sleeves 2|1 previouslydescribed with reference to Figure 13. Above the chamber 242 there areglass measuring tanks 244 which are connected to the pipe 245 leadingfrom the storage tank 44. Each tank 244 is shown provided with valvecontrolled gas and vent pipes 246 and 241. Pipes 248 extend downwardlyfrom tanks 244, and their inner ends are disposed immediately above thecontainers 239, when these containers are in filling positions. Suitablemeans is provided whereby the operator can control valves 249 forpermitting or shutting oir ilow of concentrate from tanks 244. Pipe 250connects with a suitable source of gas, whereby sterile inert gas freefrom oxygen is continuously pled into the housing 240 and continuouslyvented from this housing through pipe 25|. In addition, means can beprovided for ilushing the sterile containers with the gas as they enterthe unit.

In operating the equipment shown in Figure 3K, the various valves arearranged for easy manipulation by the operator, and the operator is alsoprovided with control means for starting and stopping the conveyor 236.When containers are placed in lling positions, a valve 249 is opened andconcentrate from the corresponding tank 244 is expelled by introductionof gas under pressure. After being filled, the container is sealed. Thusa container is filled under sterile conditions and without contact withoxygen. In connection with the maintenance of sterile conditions, it isto be presumed that these jars are sterilized, as by means of steam orotherwise,

12 before being introduced into the filling equipment. After a measuredamount of concentrate has been discharged from one of the tanks 244.this tank is again filled with concentrate by establishing communicationwith pipe 245. While the vent pipe 241 is opened.

In the foregoing reference has been made to use of oxygen-free gas invarious units of the equipment, including the dehydrating unit. I

prefer to use a gas which is sterllizlng, in addition to being inert,sterile, and substantially free from oxygen. I have found that a gascontaining a substantial amount of carbon monoxide, as for example from0.5 to 2.5%, and devoid of oxygen, will have a distinct sterilizingaction upon food material, while at the same time the absence of oxygenwill serve to prevent discoloration and chemical changes such as affecttaste, palatabillty, and vitamin content, Also I have found that asuitable gas containing from 0.5 to 2.5% of carbon monoxide andsubstantially devoid of oxygen can be obtained by the controlled burningof a suitable fuel gas (such as natural gas) with air. Suitableapparatus for forming such a gas has been `shown in Figures 15 and 16.It consists of a mixing chamber 252 which connects with the combustionchamber 253. A'ir and fuel gas pipes 254 and 255 connect tangentiallywith chamber 252. The interior of this chamber is provided withstaggered baiiles 256 to in-. sure a maximum amount of turbulence andmixing action as the air and gas pass through the length of thischamber. In chamber 253 the combustible mixture burns and the hotproducts of combustion pass through the boiler 251, the steam from whichcan be used for certain heating operations required in conjunction withthe plant equipment. The exhaust conduit 258 leading from boiler 251connects with a water spray type of cooler and washer 259. The lowerpart of this cooler is connected to the circulating pump 26| whichserves to circulate water back to the spray head 262. The gas exhaust263 from th'e washer 259 can now be used in the Fvarious units of thesystem provided, of course, that a suitable compressor or compressorsmay be employed where gas at considerable pressure is required,-

Per cent Nitrogen 86 to 90 Carbon dioxide 6.5 to 10.5 Carbon monoxide0.5 to 4 It will be apparent that this gas is absolutely sterile, due tothe temperature at which it is generated.

As previously stated, after the fruit leaves th'e hot dipping unit 32 itremains sterile, and the fruit is never permitted to contact withoxygen. In this connection note that after removal of absorbed oxygen inthe aeration unit 40, the juice is at all times contacted with anatmosphere devoid of oxygen, and also with an atmosphere which issterile. Therefore, there is no further opportunity for oxidation orcontamination with micro organisms.

In the handling of many materials, including citrus juices, I have foundit desirable to divide the dehydrating tunnel into two compartments,with the rst compartment operating at considl cause injury. Anarrangement of this character is illustrated diagrammatically in Figure17. A tunnel |86 is divided into two sections A and B, by the gate 266.Conduits 261 and 268 connect near the outlet ends of the two sections Aand B; and both lead to the cooler 269. From this cooler two conduits21| and 212 lead to the separate heaters and blowers 213 and 214, whichin turn are connected by conduits 216 and 211 at points near the inletends of the sections A and B.

In the drying of orange juice it is desirable to keep the material at atemperature not to exceed 80 F. Thus for section A, the ingoingtemperaspection of the fruit to remove rejects, the fruit i can bebriefly reviewed as follows: Following inis subjected to the preliminaryoperations ofwet scrubbing, hot dip sterilizing, and chilling in the7cold dip unit to prevent penetration of heat into the sterile andcleaned fruit. Then'the fruit is surface dried and -introduced into th'efreezing unit. Following freezing, the sterile fruit is now supplied tothe peeling unit where the peel is l removed by surface attrition. Themeat of the fruit is now disintegrated, and the disintegrated materialis then subjected to centrifugal screening to free the Juice fromcoarser pulp. The juice, which at this time contains some small amountof absorbed oxygen. is then subjected to the dispersing action of anoxygen-free insert gas, in the deaeration equipment, and is then sent.to. cold storage preparatory to concentration.

The stored fruit is then sent to the dehydrating unit where measuredquantities are placed in the drying trays, vand the drying trays arethen progressed through the dehydrating tunnel. In the dehydratingtunnel the juice is concentrated by evaporation, at relatively lowtemperatures. and with gas of the character previously described whichcontains a substantial amount of carbon monoxide, thus imparting asterilizing effect simultaneously with drying. After being concentrated,there may be an interval of further storage, after which the concentrateis introduced into sterile containers. likewise in the presence of anoxygen-free atmosphere. These containersare then sealed and provide amarketable preserved product.

My process and equipment will give remarkable results on a variety offood products. As applied to citrus fruit. like oranges, concentrationscontaining from '10 to '15%v solids are generally obtained. Thisconcentrate is a preserved product which will last indefinitely, andwhich has a relatively high vitamin content compared with the4 vitamincontent of the original material.

When re-mixed'with water to form a material having the same consistencyas the original juice,

it has a flavor practically indistinguishable from the original juice.The above properties are attributed to various features of the process,including lack'ofoxidation and the relatively low temperature treatmentthroughout. In general the temperature of the drying gas should beregulated toa value below that which will cause the food to be heated toa temperature sumcient to impair its flavor. In general the lower the`sugar content of Juices, the higher may be its temperature duringtreatment without iiavor or color impairment. As previously stated, withorange juice I have found that the juice during dehydration should bekept below about F. In general the upper temperature limit of thematerial depends upon constituents such as the sugar-acid ratio,chlorophyl, pigments and flavor esters. With green vegetables like greenpeas and lima beans. a safe upper temperature is about 110. F.,

and with vegetables like spinach. beetrtops; and' cabbage, about F.Tubers like potatoes, and also tomatoes will take temperatures as highas 212 F. Low temperatures such as specied cause no case hardening ofsolid materials. and aromatic esters. as for example esters whichsupplement flavor and which are generally found only in fresh foodmaterials, are largely retained during drying.

Use of a sterilizing sas as speciiied has been found tohave a markedeffect in promoting production of a product which will keep for longperiods without heat treatment or chemical preservatives. Analysis oforange juice concentrate made by my process reveals no trace of microorganisms such as cause mold growth, fermentation, or other form ofspoilage. and no remaining traces of carbon monoxide can be found.

Aside from its application to citrus juice, the features of my processand system can be applied to a wide variety of food products. It willbel apparent that a number of units oi' the complete system can beomitted in the handling of certain food products. For example, in usingthe process and equipment to form a tomato Juice concentrate, one simplypulps the raw tomatoes under sterile conditions, after which peel andoversized particles are removed, and the remaining material introduceddirectly into the dehydrating unit. In the handling of fruit such asapples, peaches, apricots and the like, the fresh fruit can be cut intoslices, under'sterile and Aoxygen-free conditions, and then the slicedfruit introduced into the trays of the dehydrator and subjected todehydration as previously described. l

portion of the flesh, removing the peel by surface attrition, and thendisintegrating the iiesh to free the juice.

3. In a process for the handling of citrus juice,

the steps of sterilizing the outer surfaces of the fruit, freezing thefruit to an extent at least sufficient to freeze the peel portion andthe outer portion of the flesh. and then removing the peel by surfaceattrition.

